U.S. patent number 5,498,280 [Application Number 08/338,694] was granted by the patent office on 1996-03-12 for phosphorescent and fluorescent marking composition.
This patent grant is currently assigned to Binney & Smith Inc.. Invention is credited to David C. Fistner, Colin M. Snedeker.
United States Patent |
5,498,280 |
Fistner , et al. |
March 12, 1996 |
Phosphorescent and fluorescent marking composition
Abstract
A phosphorescent and fluorescent marking composition, e.g., a
crayon, comprising both high and low molecular weight polyethylene
glycols in combination with phosphorescent and fluorescent
pigments. The composition advantageously preferably further
includes at least one filler, which preferably includes a
water-miscible filler, a water-soluble surfactant, and a
plasticizer.
Inventors: |
Fistner; David C. (Bethlehem,
PA), Snedeker; Colin M. (Bethlehem, PA) |
Assignee: |
Binney & Smith Inc.
(Easton, PA)
|
Family
ID: |
23325769 |
Appl.
No.: |
08/338,694 |
Filed: |
November 14, 1994 |
Current U.S.
Class: |
106/31.64;
106/31.86 |
Current CPC
Class: |
C09D
13/00 (20130101); C09K 11/02 (20130101); C09K
11/565 (20130101) |
Current International
Class: |
C09D
13/00 (20060101); C09D 013/00 () |
Field of
Search: |
;106/19B,21R,21A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Klemanski; Helene
Attorney, Agent or Firm: Leydig, Voit & Mayer, Ltd.
Claims
What is claimed is:
1. A marking composition comprising
(a) a high molecular weight polyethylene glycol having a molecular
weight of at least about 10,000;
(b) a low molecular weight polyethylene glycol having a molecular
weight ranging from about 100 to about 1,000;
(c) a phosphorescent pigment; and
(d) a fluorescent pigment.
2. The marking composition of claim 1, wherein the ratio of high
molecular weight polyethylene glycol to low molecular weight
polyethylene glycol in the composition on a weight percent basis is
from about 2:1 to about 1:1.
3. The marking composition according to claim 2, wherein the high
molecular weight polyethylene glycol is present in an amount
ranging from about 3 wt. % to about 30 wt. % and the low molecular
weight polyethylene glycol is present in an amount ranging from
about 2 wt. % to about 50 wt. %, all based upon the weight of the
composition.
4. The marking composition according to claim 3, wherein the high
molecular weight polyethylene glycol is present in an amount
ranging from about 5 wt. % to about 10 wt. % and the low molecular
weight polyethylene glycol is present in an amount ranging from
about 3 wt. % to about 20 wt. %, all based upon the weight of the
composition.
5. The marking composition of claim 1, wherein the high molecular
weight polyethylene glycol has a molecular weight which ranges from
about 17,000 to about 23,000.
6. The marking composition of claim 1, wherein the low molecular
weight polyethylene glycol has a molecular weight which ranges from
about 400 to about 800.
7. The marking composition of claim 1, wherein the total pigment in
the composition is at least about 15 wt. %.
8. The marking composition of claim 1, wherein the phosphorescent
pigment has an average diameter of about 11 microns to about 15
microns.
9. The marking composition of claim 8, wherein the phosphorescent
pigment is present in the composition in an amount of from about 15
wt. % to about 25 wt. %.
10. The marking composition of claim 9, wherein the fluorescent
pigment is present in the composition in an amount of from about
0.5 wt. % to about 2.0 wt. %.
11. The marking composition according to claim 1 further comprising
a filler.
12. The marking composition of claim 11, wherein the filler is
selected from the group consisting of clay, calcium carbonate,
talc, mica, and mixtures thereof.
13. The marking composition of claim 12, wherein the filler is
present in an amount of up to about 60% by weight.
14. The marking composition of claim 11, wherein the filler
comprises a water-miscible filler.
15. The marking composition of claim 14, wherein the water-miscible
filler is a stearyl alcohol.
16. The marking composition of claim 15, wherein the stearyl
alcohol is present in the composition in an amount of from about 5
wt. % to about 40 wt. %.
17. The marking composition of claim 11 further comprising a
surfactant.
18. The marking composition of claim 17, wherein the surfactant is
selected from the group consisting of mono esters of polyols and
fatty acids, diesters of polyols and fatty acids, nonionic block
copolymers of propylene oxide and ethylene oxide, ethylene oxide
condensation products, nonylphenol ethoxylates, ethyleneoxy
ethanols, polyoxyethylene ether alcohol, and mixtures thereof.
19. The marking composition of claim 18, wherein the surfactant is
selected from the group consisting of polyethylene glycol
monostearate, polyethylene glycol distearate, glycerol
monostearate, and mixtures thereof.
20. The marking composition of claim 19, wherein the surfactant is
present in an amount of up to about 30% by weight.
21. The marking composition of claim 17 further comprising a
plasticizer.
22. The marking composition of claim 21, wherein the plasticizer is
oleyl alcohol.
23. The marking composition of claim 22, wherein the plasticizer is
present in an amount of up to 10% by weight.
24. The marking composition of claim 1, wherein the composition
comprises:
(a) from about 3 wt. % to about 30 wt. % of the high molecular
weight polyethylene glycol;
(b) from about 2 wt. % to about 50 wt. % of the low molecular
weight polyethylene glycol;
(c) from about 5 wt. % to about 50 wt. % of the phosphorescent
pigment, wherein the phosphorescent pigment has an average particle
size of about 11 microns to about 15 microns; and
(d) up to about 10 wt. % of the fluorescent pigment.
25. The marking composition of claim 24, wherein said composition
further comprises:
(e) up to about 90 wt. % of a filler, wherein the filler comprises
about 5 wt. % to about 40 wt. % of a water-miscible filler;
(f) up to about 30 wt. % of a surfactant, said surfactant being
other than a liquid at room temperature; and
(g) up to about 10 wt. % of a plasticizer.
26. The marking composition of claim 25, wherein said composition
comprises:
(a) from about 5 wt. % to about 10 wt. % of the high molecular
weight polyethylene glycol, wherein the molecular weight of the
high molecular weight polyethylene glycol ranges from about 17,000
to about 23,000;
(b) from about 3 wt. % to about 20 wt. % of the low molecular
weight polyethylene glycol, wherein the molecular weight of the low
molecular weight polyethylene glycol ranges from about 400 to about
800;
(c) from about 15 wt. % to about 25 wt. % of the phosphorescent
pigment, wherein the phosphorescent pigment has a particle size of
about 14 microns;
(d) from about 0.5 wt. % to about 2 wt. % of the fluorescent
pigment;
(e) from about 25 wt. % to about 40 wt. % of the filler, wherein
the filler comprises about 25 wt. % to about 35 wt. % of a
water-miscible filler;
(f) from about 10 wt. % to about 20 wt. % of the surfactant;
and
(g) from about 2.5 wt. % to about 7.5 wt. % of the plasticizer.
27. The marking composition of claim 26, wherein said filler is
talc, said water-miscible filler is stearyl alcohol, said
surfactant is polyethylene glycol distearate, and said plasticizer
is oleyl alcohol.
Description
FIELD OF THE INVENTION
This invention relates to marking compositions and marking
instruments which contain such compositions, e.g., crayons.
BACKGROUND OF THE INVENTION
Marking instruments in the form of crayons have been used by young
and old for decades. Historically, crayons have been manufactured
by mixing together a binder, the binder typically constituting a
molten wax, and a suitable pigment. The molten mixture would then
be extruded into a desired shape, e.g., a cylinder, and
subsequently cooled to effect solidification of the mixture. The
resulting crayon, when rubbed on a surface, such as paper, would
leave a mark, i.e., a residue of pigmented wax, on the paper's
surface.
Over the years, the crayon has undergone a number of changes to
improve its appearance, mechanical properties, and marking
properties, as well as its toxicity. One of these changes, which
affects at least the appearance of the crayon, is that relating to
pigments. The introduction of new pigments over the years has
provided crayon developers with the ability to produce crayons
having a variety of vivid and attractive colors. This increase in
the availability of colors and hues in crayons has fueled the
demand for further improvements in the properties of crayons,
generally. One of the areas of crayon development which has been
affected by the foregoing may be characterized as the area of
"special effects."
One of these special effects is phosphorescence. Phosphorescence is
achieved by the use of phosphors, which are substances which emit
light when excited by radiation. Phosphors have been known for
years, and have been incorporated into different types of marking
compositions. By way of example, a phosphorescent marking
composition in the form of a crayon, pencil or chalk was described
and patented in 1882 (Horne, U.S. Pat. No. 257,706). This marking
device, however, is relatively unsophisticated, being comprised of
a phosphorescent substance, pipe clay, curd soap, gum arabic, and
water. A more recent example of a phosphorescent marking material,
which comprises a wax base vehicle, filler particles, and
phosphorescent particles, is described in U.S. Pat. No.
5,116,533.
Another aspect of the special effect area is fluorescence. This
property is obtained by the use of fluorescers, which are
substances which emit electromagnetic radiation (usually as visible
light) resulting from (and occurring only during) the absorption of
radiation from some other source. Examples of pigments which
fluoresce under daylight conditions are described in U.S. Pat. No.
3,939,093. Such fluorescent pigments have also been included in
marking compositions, e.g., U.S. Pat. No. 3,057,806, which
describes fluorescent crayons.
One U.S. patent which discloses pigment compositions which comprise
a combination of common pigments, phosphorescent pigments, and
fluorescent pigments, is U.S. Pat. No. 4,725,316. These pigment
compositions are said to be combinable with translucent plastics,
resins, and natural and synthetic rubbers. However, there is no
mention of their use in connection with crayons.
Another area of crayon technology which has undergone significant
change over the years is the composition of the binder component.
The natural waxes, which were historically used as binders, have
been improved through blending and the inclusion of additives. In
addition, synthetic materials have been developed which provide,
among other advantages, a more uniform distribution of pigment
throughout the crayon, and the ability to successfully mark a
relatively wider variety of surfaces.
One patent which is exemplary of those in which synthetic binders
are included in a crayon composition is U.S. Pat. No. 4,978,390.
The compositions disclosed therein comprise, generally,
polyethylene glycols, a pigment, certain other alcohols, and other
components. This patent specifically states, however, that only
certain polyethylene glycol binders be used in the
composition--those having a molecular weight of above 7,000.
Polyethylene glycols having a molecular weight below 7,000 should
be avoided, according to the patent.
The formulation of any marking composition which is intended to be
used in the form of a crayon should further be developed so that
the crayon provided thereby possesses good appearance, good
mechanical and marking properties, and relatively low toxicity.
More particularly, a crayon should advantageously possess
sufficient mechanical strength so it can successfully withstand
rubbing on a surface without undue crumbling or breaking. Moreover,
the crayon, when rubbed on a surface, should advantageously provide
a relatively uniform laydown, i.e., a relatively smooth and uniform
layer of the crayon composition on the surface--without undue
flaking. Further, the crayon should provide a mark which is
substantially clean, and uniform, in coloration. In addition, the
crayon should not be unduly hygroscopic in nature, i.e., it should
not absorb water to the extent that it acquires a wet feel and
looses mechanical strength.
Obtaining satisfactory levels of performance in regard to all of
the foregoing properties has not, however, been a simple matter. On
the contrary, such has been found to be problematic when new crayon
formulations are developed using components which have not
previously been included together in a crayon composition.
Thus, one of the objects of the present invention is to provide a
marking composition, e.g., a crayon, which possesses an enhanced
level of special effects.
A further object of the present invention is to provide a special
effects marking composition which is able to provide a high quality
mark on a variety of surfaces.
Another object of the present invention is to provide a special
effects marking composition which possesses good mechanical
strength.
Yet another object of the present invention is to provide a special
effects marking composition which possesses good appearance.
An additional object of the present invention is to provide a
special effects marking composition which possesses a relatively
low level of hygroscopicity.
A further object of the present invention is to provide a special
effects marking composition which possesses a relatively low level
of toxicity.
These and other objects and advantages of the present invention, as
well as additional inventive features, will be apparent from the
description of the invention provided herein.
SUMMARY OF THE INVENTION
The present invention provides a marking composition having an
enhanced level of special effects which, when provided in the form
of a crayon, provides a high quality mark on a variety of surfaces
(e.g., has good laydown and color uniformity), has good mechanical
strength and appearance, and relatively low levels of
hygroscopicity and toxicity.
The marking composition of the present invention comprises a high
molecular weight (at least about 10,000) polyethylene glycol (PEG),
a low molecular weight (from about 100 to about 1000) PEG, a
phosphorescent pigment, and a fluorescent pigment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention comprises a marking composition which
provides a certain special affect which, it is believed, has not
been available previously. More particularly, the composition
possesses both phosphorescence and fluorescence, which provides
crayons prepared from such compositions unique and appealing to
young and old alike. Specifically, such crayons, and marks made
using such crayons, will fluoresce under ordinary lighting
conditions, e.g., sunlight or illuminated rooms, and also
phosphoresce (glow) in a darkened area when the crayon or mark is
taken from an illuminated area to the darkened area.
In addition to providing the aforementioned properties, the
composition, when formed into a crayon, also provides other highly
desirable advantages. For example, it is able to provide a high
quality mark on a variety of surfaces, e.g., it has good laydown
and color uniformity, has good mechanical strength and appearance,
as well as relatively low levels of hygroscopicity and
toxicity.
The composition itself comprises: a high molecular weight PEG
having a molecular weight of at least about 10,000; a low molecular
weight PEG having a molecular weight ranging from about 100 to
about 1,000; a phosphorescent pigment; and a fluorescent
pigment.
The high molecular weight PEG should have an average molecular
weight of at least about 10,000. It has been found that PEG's of
this molecular weight, in the present composition, provide certain
benefits. One of these benefits is the ability to assist in
imparting a certain degree of mechanical strength to the
composition. This is significant because crayons should possess a
certain level of strength to withstand the rubbing that must be
undertaken to produce a mark from the crayon. These PEG's have been
found to be of significant assistance in providing such strength.
An additional benefit of these PEG's was found in respect to their
hygroscopic properties. More particularly, it was found that such
PEG's did not readily absorb water, and thereby have the effect of
not adding to the hygroscopic properties of the composition,
thereby effectively lowering the overall hygroscopic level of the
composition. This is of significance in the preparation of crayons
because a high hygroscopic level not only causes the crayon to feel
wet, but adversely effects the mechanical strength of the crayon.
It was further found that these PEG's assisted in suspending the
relatively large phosphorescent pigments in the composition,
providing uniformity in the phosphorescent pigment distribution
during processing of the composition into a crayon, and providing
for the uniform distribution of that pigment in a mark made using
the resulting crayon.
Advantageously, the molecular weight of the high molecular weight
PEG's may range above about 15,000, and may preferably range
between about 17,000 and about 23,000. PEG's within this range were
found to provide optimal performance in the areas of mechanical
strength, hygroscopic levels, and phosphorescent pigment
suspension. An example of a preferred PEG is the water-miscible
PEG, Carbowax.RTM. 20M (Union Carbide).
This component should generally be included in an amount which is
sufficient to provide the composition with the desired level of
strength, hygroscopic properties, and phosphorescent suspension
capability, without also providing the composition with a viscosity
which is too high to be processed into a useful article, e.g., a
crayon. Advantageously, this high molecular weight PEG should be
provided in an amount ranging from about 3 wt. % to about 30 wt. %,
and preferably from about 5 wt. % to about 10 wt. %, of the
composition.
In addition to a high molecular weight PEG, the composition further
includes a low molecular weight PEG. This PEG has a molecular
weight of between about 100 and 1,000. It was found that, in
respect to the present composition which includes fluorescent and
phosphorescent pigments, inadequate laydown was experienced in the
absence of such a low molecular weight PEG. Thus, a sufficient
level of this PEG should advantageously be provided in the
composition so that the composition, if formulated into a crayon,
possesses good laydown and other marking properties, e.g.,
providing for an even distribution of the composition onto a
substrate, and the ability to mark a substrate without the
application of undue force to the crayon. However, and
advantageously, the amount of this component should be limited so
that the mechanical properties of the crayon are not unduly
compromised.
More advantageously, the ratio of the high molecular weight
polyethylene glycol to the low molecular weight polyethylene glycol
in the composition, on a weight percent basis, is from about 2:1 to
about 1:1. On an absolute basis, this low molecular weight PEG is
advantageously present in an amount ranging from about 2 wt. % to
about 50 wt. %, preferably from about 3 wt. % to about 20 wt. %,
and most preferably from about 5 wt. % to about 15 wt. %, based
upon the weight of the composition.
Preferably, the low molecular weight PEG comprises a PEG having a
molecular weight of from about 400 to about 800. Exemplary of such
a PEG is a water-miscible PEG, Carbowax.RTM. 540 (Union
Carbide).
A further component of the marking composition is a phosphorescent
pigment which provides the composition with its "glow in the dark"
property. Any phosphorescent pigment may be used in the
composition, so long as it does not adversely affect the marking
characteristics of the composition, or adversely interact with any
of the other components of the composition. For example, in the
case of calcium sulfide phosphors, hydrogen sulfide gas could be
released therefrom, in which case a different phosphorescent
pigment should be used, or the calcium sulfide phosphor should be
encapsulated.
Examples of phosphorescent pigments which are suitable for use in
the present marking composition include, among others, zinc sulfide
phosphors, aluminate phosphors, and calcium sulfide phosphors. Zinc
sulfide phosphors are a preferred type of phosphor for use in the
marking composition because of their relatively high luminous
intensity, stability when contacted with water, and low
toxicity.
In addition to the foregoing considerations, it was found that it
was also desirable that the average particle size of the phosphors
be within a certain range. More specifically, if the average
particle size is too small, the "glow" provided thereby will lack
intensity and duration. If, on the other hand, the average particle
size is too large, the laydown will be adversely affected, e.g., it
will become vary scratchy when the crayon is rubbed against a
writing surface. This scratchiness prevents a build-up of crayon
material on the surface because repeated rubbing tends to scrape
off previously laid-down material. It was determined that the
particle size may preferably range from about 11 microns to about
15 microns, with a particle size of about 14 microns being most
preferred.
In addition to the size of the particles, the amount of
phosphorescent pigment included in the marking composition was also
determined to be of significance. For example, too little phosphor
in the composition will not produce a sufficient level of "glow,"
while an excessive level will affect laydown by providing a harder
crayon which writes less smoothly and by decreasing the crayon's
mechanical strength. Advantageously, the amount of phosphorescent
pigment that is included in the composition may range from about 5
wt. % to about 50 wt. %, based on the weight of the composition.
Preferably, the amount of phosphorescent pigment in the composition
may range from about 15 wt. % to about 25 wt. %, and most
preferably it will constitute an amount of about 20 wt. % of the
composition.
The present marking composition further comprises a fluorescent
pigment. This pigment provides the "day glow" properties to the
marking composition. As was the case in respect to the
phosphorescent pigment, any fluorescent pigment may be used so long
as it does not adversely effect the marking characteristics of the
composition, or adversely interact with any of the other components
of the composition.
Further, however, the amount of pigment that is included will have
an impact on the properties of the composition. For example, if too
much pigment is used, it will assist in lessening the "glow in the
dark" property provided by the phosphorescent pigment. Conversely,
too little fluorescent pigment will provide insufficient "day glow"
color. Preferably, the fluorescent pigment may be provided up to
about 10 wt. % of the composition. More preferably, the fluorescent
pigment may be provided so that it comprises from about 0.5 wt. %
to about 2.0 wt. % of the composition, and most preferably about
1.6 wt. % thereof.
Other optional components may be included in the marking
composition to provide it with certain additional, and desirable,
properties. One of these is a filler. The filler selected should be
inert in regard to the other components of the composition, and is
advantageously selected and provided so as to provide the
composition with characteristics which are desirable from a
processing perspective.
The composition may comprise up to about 90% by weight of filler.
However, the amounts of filler included therein should not be so
great as to adversely affect the other desirable properties of the
marking composition, such as smoothness of writing, mechanical
strength, and color intensity. Advantageously, filler is present in
an amount up to about 60 wt. %, preferably from about 15 wt. % to
about 50 wt. %, and most preferably from about 25 wt. % to about 40
wt. % of the composition.
Preferably, the filler will comprise both a water-insoluble filler
and a water-miscible filler. Examples of suitable water-miscible
fillers include hydrocarbon-based water-miscible fillers such as
C.sub.14-18 alcohols, e.g., stearyl alcohol, cetyl alcohol, and
myristal alcohol, among others, with stearyl alcohol being
preferred. Examples of water-insoluble fillers which are suitable
for use include clay, calcium carbonate, talc and mica, with talc
being preferred, due to its relatively small particle size and
translucence. An example of a preferred talc product is Nytal 400
(R. T. Vanderbilt Co., Inc., Norwalk, Conn.).
When both water-insoluble and water-miscible fillers are included
in the composition, they may advantageously be present in certain
weight ranges, i.e., in respect to the water-insoluble filler, from
about 2 wt % to about 20 wt % and from about 5 wt. % to about 40
wt. % of the water-miscible filler. Preferably, they may be present
at from about 5 wt. % to about 15 wt. % and from about 25 wt. % to
about 35 wt. %, and most preferably present at about 7 wt. % and
about 30 wt. %, respectively.
Another component which is advantageously included in the marking
composition is a water-soluble surfactant. This surfactant should
be other than a liquid at room temperature, so that it does not
adversely affect the marking characteristics of a crayon formed
using the composition. Further, and advantageously, the surfactant
should possess good dimensional stability and exist as a solid or
semi-solid material, such as a paste, at room temperature. The
surfactant functions in various ways, e.g., modifies the
consistency of the composition, thereby modifying the marking
characteristics of the composition, enhances the laydown of the
composition, enhances the compatibility of the various components
of the composition, facilitates the mixing of the composition by
acting as a dispersant for the various non-soluble components of
the composition, particularly the pigments, and contributes to the
release of the composition from a mold.
Preferably, the surfactant is one or more of a mono ester of a
polyol or fatty acid, a diester of a polyol or fatty acid, a
nonionic block copolymer of propylene oxide and ethylene oxide, an
ethylene oxide condensation product, a nonylphenol ethoxylate, an
ethyleneoxy ethanol, or a polyoxyethylene ether alcohol. Using
mixtures of these materials is advantageous when preparing articles
containing the present composition under specific manufacturing
conditions, and for obtaining a proper balance of properties in a
particular form of the composition. More specifically, and
especially if the composition is to be employed in a gravity-molded
crayon product, the surfactant is preferably a PEG monostearate,
PEG distearate, glycerol monostearate or a mixture thereof, with a
mixture of PEG monostearate and PEG distearate being particularly
preferred. The PEG monostearate has been found to provide such a
product with a softer laydown, while PEG distearate tends to harden
the laydown.
The surfactant is preferably present in the composition in an
amount which provides the desired properties in the composition, as
set forth in a previous paragraph, without unduly adversely
affecting the mechanical properties of a crayon formed therefrom.
This amount will generally range up to about 30 wt. % of the
composition. Preferably, the surfactant may be included in an
amount of from about 10 wt. % to about 20 wt. %, and most
preferably in an amount of about 18 wt. % of the composition.
The marking composition may further include a plasticizer.
Advantageously, the plasticizer comprises a non-volatile liquid at
room temperature. Particular preferred plasticizers are alcohols,
with oleyl alcohol being preferred because it possesses high
lubricity. The plasticizer, if included in the composition, is
advantageously present in an amount which assists in providing the
composition with good laydown, while not unduly adversely affecting
the mechanical properties of the composition. Advantageously, this
component may be present in an amount up to about 10 wt. % of the
composition. More preferably, the plasticizer is present in the
marking composition in an amount of from about 2.5 wt. % to about
7.5 wt. %, and most preferably in an amount of about 5 wt. %.
The compositions of the present invention may be fabricated in any
form of marking utensils, e.g., crayons, by any suitable means.
Methods for accomplishing this are well known to those skilled in
the art, and accordingly will not be recited herein. Other forms of
the present marking composition, e.g., marking pencils and
injection molded marking instruments and the like are, of course,
within the scope of the present invention. Thus, the following
examples are set forth by way of illustration only, and are not
intended to limit the scope of the present invention in any
manner.
EXAMPLE 1
This example describes the preparation of a crayon prepared in
accordance with the present invention.
7.5 wt. % of Carbowax.RTM. 20M (a high MW (17,500 to 22,500) PEG,
available from Union Carbide), 18.5 wt. % Kessco PEG 6000 DS (a
distearate, available from Stepan Company, Northfield, Ill.), 32.4
wt. % TA-1618 (a C.sub.14-18 alcohol (stearyl alcohol), available
from Proctor & Gamble), and 5.0 wt. % Carbowax.RTM. 540 (a low
MW (500-600) PEG, available from Union Carbide) were mixed in a
kettle at 240.degree. F. 7.5 wt. % of Witcohol 85 NF (oleyl
alcohol, available from Witco Corporation, Dublin, Ohio) was then
added to the mix kettle. Then, in sequence, about 7.5 wt. % Nytal
400 (an industrial talc), 1.6 wt. % fluorescent pigments (from the
Radiant MP series of pigments, available from Magruder Color Co.,
Richmond, Calif.), and 22.5 wt. % phosphorescent pigment (zinc
sulfide phosphor pigment, available from USR Optonix, Inc.,
Hackettstown, N.J.) were added to the mix kettle under high-speed
mixing. The resulting marking composition was then molded into
crayons.
The crayons prepared thereby glowed in the dark and in the light,
had good mechanical strength, reduced hygroscopic properties,
increased viscosity, essentially uniform suspension of the
phosphorescent and fluorescent pigments, and enhanced laydown.
EXAMPLES 2-6
These examples demonstrate the preparation of crayons prepared in
accordance with the present invention.
TABLE A ______________________________________ Ex. 2 Ex. 3 Ex. 4
Ex. 5 Ex. 6 ______________________________________ Carbowax .RTM.
20M 8.4 7.9 8.4 8.6 8.6 Kessco PEG 6000 20.8 19.4 20.8 21.2 21.2 DS
TA-1618 36.5 33.8 36.5 37.0 37.0 Witcohol 85 NF 5.6 5.2 5.6 5.7 5.7
Carbowax .RTM. 540 5.0 5.0 5.0 5.0 5.0 Nytal 400 7.5 7.5 7.5 7.5
7.5 Nichia NP-231.sup.1 15.0 20.0 -- 13.5 12.0 MP-BL5527.sup.2 1.2
1.2 -- -- -- MP-GR5546.sup.3 -- -- 1.2 -- -- Nichia NP-230.sup.4 --
-- 15.0 1.5 3.0 ______________________________________ .sup.1
Nichia NP231 is a dysprosium europium strontium aluminate (blue)
phosphorescent pigment (Nichia America Corporation, Lancaster,
Pennsylvania). .sup.2 MP-BL5527 is a blue fluorescent microsphere
pigment (Magruder Colo Co., Richmond, California). .sup.3 MP-GR5546
is a green fluorescent microsphere pigment (Magruder Color Co.,
Richmond, California). .sup.4 Nichia NP230 is a dysprosium europium
strontium aluminate (blue) phosphorescent pigment (Nichia America
Corporation, Lancaster, Pennsylvania).
The marking compositions of Examples 2-6 were then molten and
molded into crayons. The resulting crayons glowed blue in the dark
(the crayon of Example 4, however, glowed green) and appeared blue
(the crayon of Example 4, however, appeared green) in the light,
had good mechanical strength, reduced hygroscopic properties,
increased viscosity, essentially uniform suspension of the
phosphorescent and fluorescent pigments, and enhanced laydown.
EXAMPLES 7-11
These examples demonstrate the effect of the low molecular weight
PEG on the laydown and hygroscopic properties of the marking
compositions.
TABLE B ______________________________________ Ex. 7 Ex. 8 Ex. 9
Ex. 10 Ex. 11 ______________________________________ Carbowax .RTM.
20M 8.1 7.8 7.8 7.5 7.5 Kessco PEG 6000 20.0 19.2 19.2 18.5 18.5 DS
TA-1618 34.9 33.7 33.7 32.4 32.4 Witcohol 85 NF 5.4 5.2 5.2 5.0 5.0
Carbowax .RTM. 540 0.0 2.5 2.5 5.0 5.0 Nytal 400 7.5 7.5 7.5 7.5
7.5 USR 2330 MBW.sup.1 22.5 22.5 22.5 22.5 22.5 Radiant Lab MP 1.6
1.6 -- 1.6 -- Series (Ref. 5480).sup.2 Radiant Lab MP -- -- 1.6 --
1.6 Series (Ref. 5481).sup.3 ______________________________________
.sup.1 USR 2330 MBW is a zinc sulfide phosphorescent pigment (14
.mu.m average pigment diameter) (USR Optonix, Inc., Hackettstown,
New Jersey). .sup.2 Radiant Lab Ref. 5480 is a magenta fluorescent
pigment (Magruder Color Co., Richmond, California). .sup.3 Radiant
Lab Ref. 5481 is a fluorescent pigment (Magruder Color Co. red
Richmond, California).
The marking compositions of Examples 7-11 were then melted and
molded into crayons. The data from these exemplary compositions
demonstrate that, as the percent weight composition of low
molecular weight PEG increases, the softness of the crayon
increases and the laydown of the crayon improves.
EXAMPLES 12-16
These examples demonstrate how the quantity of filler in the
composition affects the laydown of the resulting marking
composition.
TABLE C ______________________________________ Ex. 12 Ex. 13 Ex. 14
Ex. 15 Ex. 16 ______________________________________ Carbowax .RTM.
8.3 8.3 8.3 8.2 8.0 20M Kessco PEG 20.5 20.5 20.5 20.3 19.7 6000 DS
TA-1618 35.8 35.8 35.8 35.6 34.5 Witcohol 85 3.6 3.6 3.6 5.4 5.3 NF
Carbowax .RTM. -- -- -- 3.0 5.0 540 Nytal 400 11.8 11.8 11.8 7.5
7.5 UMC GBU.sup.1 20.0 19.0 19.0 19.0 19.0 Radiant T1-CH6610 -- 1.0
-- -- -- (16-3312).sup.2 Radiant T1-DG6621 -- -- 1.0 1.0 1.0
(16-3313).sup.3 ______________________________________ .sup.1 UMC
GBU is a zinc sulfide phosphorescent pigment (United Mineral &
Chemical Corporation, Lyndhurst, New Jersey). .sup.2 16-3312 is a
fluorescent pigment (Magruder Color Co., Richmond, California).
.sup.3 16-3313 is a fluorescent pigment from (Magruder Color Co.,
Richmond, California).
The marking compositions of Examples 12-16 were melted and molded
into crayons. This example demonstrates that, as the weight percent
of filler in the composition increases, the crayon becomes harder
and flakes, indicating a decrease in laydown.
EXAMPLES 17-21
Further examples of crayon formulations prepared in accordance with
the present invention are provided.
TABLE D ______________________________________ Ex. 17 Ex. 18 Ex. 19
Ex. 20 Ex. 21 ______________________________________ Carbowax .RTM.
7.5 7.0 6.9 6.9 7.0 20M Kessco PEG 18.5 17.2 17.0 17.0 17.2 6000 DS
TA-1618 32.5 30.2 29.9 29.9 30.2 Witcohol 85 5.0 4.6 4.6 4.6 4.6 NF
Carbowax .RTM. 10.0 10.0 10.0 10.0 10.0 540 Nytal 400 10.0 12.5
10.0 10.0 5.0 6SSUY.sup.1 15.0 17.5 20.0 -- 25.0 Radiant T1-DG6621
1.5 1.0 1.6 -- 1.0 (16-3313) GSS 305/8.sup.2 -- -- -- 21.6 --
______________________________________ .sup.1 6SSUY is a zinc
sulfide phosphorescent pigment (United Mineral & Chemical
Corporation, Lyndhurst, New Jersey). .sup.2 GSS 305/8 is blend of a
zinc sulfide phosphorescent pigment (92 wt %) and a fluorescent
pigment (8 wt. %) (United Mineral & Chemical Corporation,
Lyndhurst, New Jersey).
The marking compositions of Examples 17-21 were melted and molded
into crayons. All of the compositions provided crayons which
possessed good phosphorescent and fluorescent properties.
All of the references cited herein, including patents, patent
applications, and publications, are hereby incorporated in their
entireties by reference.
All percentages set forth herein, unless otherwise specified, are
provided in weight percent of the composition.
While this invention has been described with an emphasis upon
preferred embodiments, it will be obvious to those of ordinary
skill in the art that variations of the preferred embodiments may
be used and that it is intended that the invention may be practiced
otherwise than as specifically described herein. Accordingly, this
invention includes all modifications encompassed within the spirit
and scope of the invention as defined by the following claims.
* * * * *